GaN/Al_xGa_(1-x)N量子点中类氢杂质的结合能

Binding energy of a hydrogenic-like impurity in GaN/Al_xGa_(1-x)N quantum dots

利用有效质量方法和变分原理,考虑内建电场(BEF)效应和量子点的三维约束效应,研究了纤锌矿结构的GaN/A lxGa1-xN柱形量子点中类氢杂质的结合能随量子点高度、A l含量和杂质位置的变化规律。结果表明:类氢杂质位于量子点中心时,杂质结合能随量子点高度的增加先增大后减小,存在最大值;随着A l含量的增加,杂质结合能增大。而杂质从量子点下界面沿Z轴上移至上界面时,杂质结合能先增大后减小,存在最大值。

In this paper, we investigate the binding energy of a hydrogenic -like impurity as function of the height of QDs, Al content and the hydrogenic - like impurity position for an cylindrical wurtzite GaN/AlxGa1-xN QD within the framework of effective - mass approximation and a variational approach, including three -dimensional confinement in QDs and a strong built- in electric field effect.The numerical results show that when the hydrogenic - like impurity in the center of QDs, the binding energy first increases rapidly, reachs a maximum value, then slowly decreases with increasing the height of QDs. With increasing Al content, the binding energy of hydrogenic - like impurity increases. The dependence of binding energy on the impurity - center position is also considered. The binding energy of hydrogenic - like impurity firstly increases, and then decreases with moving the impurity position from the bottom of QD to the top. There is a maximum.